Postfix relaying : email to multiple addresses with one relay

I have postfix installed on an ubuntu server so my website can hand it email to relay onto sendgrid.net.

Before I installed postfix I setup swiftmailer to send the email directly to sendgrid.net, and when there were multiple email addresses, it was sent on and handled as one email with multiple addresses.

I can't get postfix to work the same way though, when it receives an email that has multiple email addresses, it sends a separate relay for each address. That is eating up my sendgrid.net daily credits very quickly.

How can I configure postfix to send on just one relay per email, instead of one relay per address.

Thanks for any pointers or help,

Mike

An example from my mail.log, showing an email that was sent to "email1@company.com; email1@company.com; email3@company.com"

Feb  4 14:32:52 ip-10-114-153-165 postfix/smtpd[11954]: connect from localhost[127.0.0.1]
Feb  4 14:32:52 ip-10-114-153-165 postfix/smtpd[11954]: A4F4F4A09B: client=localhost[127.0.0.1]
Feb  4 14:32:52 ip-10-114-153-165 postfix/pickup[11804]: B6E874A09D: uid=33 from=<noreply@business.com>
Feb  4 14:32:52 ip-10-114-153-165 postfix/smtpd[11954]: disconnect from localhost[127.0.0.1]
Feb  4 14:32:52 ip-10-114-153-165 postfix/cleanup[11957]: B6E874A09D: message-id=<1296829972.4d4c0e1488511@subdom.business.com>
Feb  4 14:32:52 ip-10-114-153-165 postfix/qmgr[23180]: B6E874A09D: from=<noreply@business.com>, size=24223, nrcpt=8 (queue active)
Feb  4 14:32:53 ip-10-114-153-165 postfix/smtp[11959]: B6E874A09D: to=<email1@company.com>, relay=smtp.sendgrid.net[174.36.32.204]:587, delay=0.93, delays=0.14/0.01/0.32/0.47, dsn=2.0.0, status=sent (250 Delivery in progress)
Feb  4 14:32:53 ip-10-114-153-165 postfix/smtp[11959]: B6E874A09D: to=<email2@company.com>, relay=smtp.sendgrid.net[174.36.32.204]:587, delay=0.93, delays=0.14/0.01/0.32/0.47, dsn=2.0.0, status=sent (250 Delivery in progress)
Feb  4 14:32:53 ip-10-114-153-165 postfix/smtp[11959]: B6E874A09D: to=<email3@company.com>, relay=smtp.sendgrid.net[174.36.32.204]:587, delay=0.93, delays=0.14/0.01/0.32/0.47, dsn=2.0.0, status=sent (250 Delivery in progress)
Feb  4 14:32:53 ip-10-114-153-165 postfix/qmgr[23180]: B6E874A09D: removed